Vaporization pipe with flame filter

ABSTRACT

A vaporizer device that uses a flame for vaporizing flavor and psychoactive compounds from smoking materials such as tobacco. The present device has a filter unit  34  with a porous flame filter  36 . The flame filter  36  can be made of open-cell ceramic or metal foam, sintered ceramic or metal granules or other porous, heat resistant materials. In use, flame is supplied to the flame filter, and inhalation causes ambient air to enter the flame filter as well. The flame exhaust and ambient air are mixed within the flame filter and produce an air stream of intermediate temperature. The intermediate temperature air stream is hot enough to vaporize desirable components from the smoking material. The filter unit and pipe can attach with a ground glass joint.

RELATED APPLICATIONS

The present application is a continuation-in-part of copending patentapplication Ser. No. 10/639,344, filed on Aug. 12, 2003 and which claimsthe benefit of priority from the following provisional patentapplications: 60/366,809 filed on Mar. 22, 2002; 60/384,551 filed on May29, 2002; 60/399,465 filed on Jul. 29, 2002; and 60/429,120 filed onNov. 26, 2002, which are hereby incorporated by reference in theirentirety.

FIELD OF THE INVENTION

The present invention relates generally to smoking devices andvaporization devices. More particularly, the present invention relatesto a pipe designed to provide vaporization by using heat from a flame.

BACKGROUND OF THE INVENTION

Tobacco, kinnick kinnick, or other herbs are typically smoked by burningand inhaling the combustion fumes and smoke. In recent years, interesthas grown in the technique of vaporization in which the smoking materialis carefully heated so that the desired flavor and psychoactivecomponents are liberated, and combustion is minimized.

Vaporization provides many benefits over smoking. When performedproperly, vaporization does not produce nearly as much toxic andcarcinogenic pyrolytic products as smoking. Also, vaporization issmoother and more flavorful, and lacks a burned taste that many finddisagreeable. Further, vaporization allows more efficient use of smokingmaterials, since desired flavor and psychoactive compounds are notdestroyed by combustion.

However, vaporization is difficult to perform, since vaporization onlyoccurs in a relatively narrow temperature range. If the temperature istoo low, desired compounds are not volatilized and nothing is inhaled;if the temperature is too high, combustion will occur, with its illeffects. For most smoking materials, vaporization is optimal in atemperature range of about 300-400 degrees Fahrenheit. The optimaltemperature depends upon the compounds being vaporized.

Most vaporizers in use today are electrically powered. For vaporizingplant materials such as tobacco or essential oils, atemperature-controlled heat gun is often used. Electrical vaporizationdevices are inconvenient to use since they are not portable and requireelectrical line power. Typically, heat guns require several hundredwatts of power. Also, electrical vaporization devices tend to beexpensive.

Some vaporizer devices employ a burning carbonaceous fuel element as aheat source. These devices are best suited for use in cigarettes sincethe carbonaceous fuel element burns for several minutes. However, acontinuously burning fuel element is not desired for vaporizing somematerials. Exemplary vaporizer devices in the prior art are listedbelow:

U.S. Pat. No. 4,219,032 describes a smoking device using a fuel element.

U.S. Pat. No. 5,993,748 describes a vaporization device that iselectrically powered.

U.S. Pat. No. 4,141,369 describes a vaporization device that iselectrically powered.

U.S. Pat. No. 6,354,301 describes a vaporizer attachment for a pipe sothat the pipe can be coupled to an electric heat gun.

U.S. Pat. No. 4,303,083 describes a vaporizer that is electricallypowered.

It would be an advance in the art of vaporization devices to provide avaporizer that operates without electrical power, is inexpensive, iseasily transportable, is small, and is simple to operate. Such a devicecould be widely used by tobacco smokers and by users of medicinal herbs(e.g. mullein, kinnick kinnick) and essential oils. Such a device wouldalso largely avoid the harmful effects of inhaling toxic pyrolyticcompounds found in smoke and provide the other benefits of vaporization.

SUMMARY

The present invention includes a vaporization device having a pipe witha bowl for holding smoking material (e.g. tobacco or other medicinalplant-based materials), and a heat resistant and porous flame filter forreceiving a flame, wherein the flame filter has a thickness of at least0.02 inches. The flame filter can also have thickness of at least 0.1inch, or in the range of 0.125-1 inches. In one embodiment, the flamefilter is made of open cell ceramic foam, which can comprise siliconcarbide, silicon, cordierite or other ceramics. The flame filter causesmixing between flame exhaust and ambient air.

The flame filter can also be made of bonded granules (e.g. sinteredmetal or ceramic granules), stacked discs (with each disc having atleast one hole), a tangled lump of metal wire, or stacked screens, forexample. Generally, the flame filter material should have a thermalconductivity of at least 30 W/mK. The pipe can also have an airflowshutter to automatically regulate the amount of airflow into the flamefilter, and thereby regulate the temperature. The device can also have ameans for indicating temperature, such as an electronic temperaturesensor with a display, or a bimetallic strip that moves in response totemperature.

In one useful embodiment, the flame filter comprises open cell siliconcarbide foam made by chemical vapor deposition. The foam can have about40-120 or 60-100 pores-per-inch (PPI), for example.

The present invention also may have a filter housing for holding theflame filter. The filter housing can be made of thermally insulatingmaterial (e.g. wood) so that a user is protected from touching the hotflame filter. The filter housing can also be hollow to provide thermalinsulation.

The present invention also includes a filter unit having a filterhousing, a flame filter disposed in the housing, and a means forattaching the filter housing to a pipe. The filter unit of the presentinvention can be used with many different kinds and styles of smokingpipes and will transform conventional smoking pipe into a vaporizationpipe. The means for attaching the pipe can be a threaded connection,magnet, clamp, hinge, ground glass joint, O-ring seal and the like.

DESCRIPTION OF THE FIGURES

FIG. 1 shows a cross-sectional side view of a vaporization pipeaccording to the present invention.

FIG. 2 illustrates the present vaporization pipe in operation.

FIG. 3 shows a close-up of a filter unit according to the presentinvention.

FIGS. 4 a and 4 b show an alternative embodiment of the invention havinga hinged filter unit, and a straight pipe.

FIG. 5 shows an alternative embodiment of the invention having afriction-fit filter unit.

FIG. 6 shows an embodiment wherein the flame filter is a stack ofscreens (metal or ceramic).

FIG. 7 shows an embodiment wherein the flame filter is a tangled web ofwire.

FIG. 8 shows a close-up of the filter unit where the flame filtercomprises a stack of 5 discs with holes.

FIGS. 9 and 10 show top view of exemplary discs possible in theembodiment of FIG. 9.

FIG. 11 shows a close-up of the filter unit where the flame filter iscombined with a disc having holes that directs heat to the periphery ofthe flame filter.

FIG. 12 is a top view of an exemplary disc that can be used in theembodiment of FIG. 11.

FIG. 13 shows an embodiment having an electronic temperature sensor andtemperature display.

FIG. 14 shows an embodiment having a mechanical airflow shutterresponsive to temperature for regulating temperature.

FIGS. 15 a and 15 b show top views of an exemplary airflow shutterusable in the embodiment of FIG. 14.

FIG. 16 shows an embodiment having a theromechanical element forindicating temperature inside the device.

FIG. 17 shows an embodiment where the flame filter is permanentlyattached to the pip, and the bowl has a door for accessing and insertingthe smoking material.

FIG. 18 shows an embodiment where a portion of the filter housing ispart of the door.

FIGS. 19 and 20 show embodiments made of glass and having ground glassjoints for attaching the bowl and the filter housing.

FIG. 21 shows an embodiment made of glass having the flame filterdisposed in a male joint.

FIG. 22 shows the embodiment of FIG. 21 in operation.

FIG. 23 shows an embodiment in which the bowl is disposed in a malejoint, and the filter housing comprises a female ground glass joint.

FIG. 24 shows a closeup view of the filter housing and joints of FIG.23.

FIG. 25 shows an embodiment with an O-ring seal between the pipe andfilter housing.

DETAILED DESCRIPTION

The present invention provides a vaporizing pipe that vaporizes flavorcompounds, medicinal compounds and psychoactive compounds from smokingmaterial such as tobacco, mullein, passion flower, cloves, yohimbe,mint, tea, eucalyptus, chamomile and the like. Many of these plantmaterials have medicinal compounds that can be inhaled when vaporized.

The present vaporizer pipe can be used with a flame such as from aconventional butane lighter or a match. The vaporization pipe of thepresent invention has a heat resistant, porous flame filter disposedupstream from the smoking material. In operation, flame exhaust andambient air are drawn into the flame filter. The flame filter causesmixing between the flame exhaust and ambient air, and also conducts heatbetween the flame exhaust and ambient air. The flame filter therebycreates an intermediate temperature (e.g. about 300-400 F) air streamcapable of vaporizing without burning. The smoking material is in thepath of the intermediate temperature air stream, and so volatile flavorand psychoactive compounds are vaporized from the smoking material. Theintermediate temperature air stream and vaporized compounds are theninhaled. The flame filter can be made of many heat-resistant materialssuch as metals (e.g. refractory metals, noble metals), ceramics and thelike. The material of the flame filter should be resistant to oxidationat high temperature, resistant to cracking under extreme thermal shock,and have a high thermal conductivity. In preferred embodiments of theinvention, the flame filter comprises open-cell ceramic foam.

Definitions:

Heat resistant: Capable of not melting and maintaining its physicalstructure when exposed to heat from a small flame. Materials thatoxidize slightly when exposed to flame (e.g. bronze, stainless steel)are considered heat resistant in the invention. However, combustiblematerials (e.g. carbon) are not heat resistant.

Porous: Having flow paths that create mixing of flame exhaust and air.

FIG. 1 is a cross sectional side view of the present vaporization pipe.The pipe has a pipe bottom 20 having a hole 22 through which vapor isinhaled. The pipe has an inhalation end 24 for contact with a usersmouth during use. The pipe also has a bowl 26 for holding smokingmaterial 28, such as tobacco or other herbs or essential oils. The bowl26 preferably 25 has a mesh screen 30 for supporting the smokingmaterial. A filter unit 34 is removably attached to the bowl 26 bythreaded connection 32. The filter unit 34 has a heat-resistant andporous flame filter 36 and a filter housing 38 surrounding the flamefilter 36. The filter unit 34 may optionally have a heat shield 40disposed between the filter housing 38 and the flame filter 36. The heatshield 40 can be a thin sheet (0.002″) of stainless steel foil, forexample. A 30 corner heat shield 41 can also be provided at an openingin the filter housing 38. The corner heat shield 41 and heat shield cancomprise a single component. The corner heat shield 41 helps protect thefilter housing 38 from flame. The filter unit 34 may make an airtightseal with the bowl 26, but an airtight seal is not absolutely requiredin the invention; a small amount of air leakage is permissible.

If essential oils are used, the smoking material can comprise glass orstainless steel wool, or ceramic foam or paper with the oil absorbedtherein. The wool or foam will function as an inert carrier and willallow the essential oil to vaporize without dripping down into the pipe.

The pipe bottom 20 and filter housing 38 can be made of many differentmaterials such as wood, glass, ceramic, metal or the like. Materialswith low thermal conductivity such as wood are generally preferred, butnot required in the invention. The filter housing 38 should also be madeof a material with low thermal conductivity so that heat from the flamefilter 36 does not escape to the exterior surfaces. The filter housing38 can be made of wood, closed-cell ceramic foam, metal or the like.Alternatively, the filter housing has a hollow space 42 to provide lowthermal conductivity. The pipe bottom 20 can also have a hollow space(not shown) for thermal insulation. The bowl 26 can be made of metal(e.g., stainless steel or brass), in which case it may be plated with arelatively chemically nonreactive metal such as silver, gold, platinumor chromium.

The present invention necessarily includes the porous flame filter 36.The flame filter is made of heat resistant material such as ceramic ormetal (e.g. refractory metal). The flame filter is made of porousmaterial. The flame filter can be made of many structures, such as opencell foam (ceramic or metal), sintered or bonded ceramic or metalgranules, stacked ceramic or metal screens or porous plates, coils ortangled lengths of wire, or stacked discs with holes. If plates areused, the plates can each have many holes or a single hole. A stack ofplates with holes or a hole is considered to be porous in the invention,even if the plates are made of nonporous material.

FIG. 2 shows the pipe of the present invention in operation. Inoperation, smoking material 28 is disposed in the bowl, and a user (notshown) inhales air and vaporization products from the inhalation end 24,as indicated by arrow 44. Flame 46 is provided to the flame filter 36 bya lighter 48 or other flame source, such as a match. The flame may ormay not touch the flame filter, but it is best for the flame to be heldslightly above the flame filter 36. Hot exhaust from the flame 46 isdrawn into the flame filter 36. Cold, ambient air 50 is also drawn intothe flame filter. The flame filter 36 causes mixing and heat exchangebetween the flame exhaust and ambient air. The flame exhaust and ambientair, after mixing and exchanging heat in the filter 36, form anintermediate-temperature air stream 52 that flows through the smokingmaterial. The intermediate-temperature air stream 52 can have atemperature of about 250-500 degrees Fahrenheit, depending on a numberof factors such as the speed of inhalation, the size and temperature ofthe flame 46, and the temperature of the ambient air. More typically,the temperature of the air stream 52 will be about 275-400 F. Bycontrolling the application of flame to the flame filter 36 (e.g.lifting or lowering the lighter), the speed of inhalation, and the sizeof the flame, a user can modulate the temperature of the air stream 52.With experience, a user can determine the temperature by taste and mouthsensations, and adjust the amount of flame accordingly to obtain aperfect temperature for vaporization.

Preferably in the invention, the flame filter 36 and bowl 26 are locatedso that the intermediate temperature air stream 52 flows straightthrough the smoking material. For example, in FIG. 2, the airflow pathfrom the filter 36 to the pipe bottom 20 extends in a straight linethrough the smoking material 28. Forcing hot air to flow through thesmoking material 28 increases vaporization of compounds from the smokingmaterial.

FIG. 3 shows a close-up view of the filter unit 34 of the presentinvention. The flame filter 36 has a thickness 54, which is measured inthe direction of airflow through the filter 36. In the presentinvention, the flame filter 36 must have a thickness 54 of at least 0.02inches. A thickness of 0.02 inches is the absolute minimum required forat least partially adequate mixing and heat exchange between the flameexhaust and ambient air. If the filter is thinner than 0.02 inches, thenthe flame will tend to bum the smoking material. More preferably, theflame filter has a thickness of at least 0.05 inches, 0.1 inches, 0.125inches or 0.2 inches. A thicker flame filter provides more even heatingof the smoking material, and tends to provide lower temperatures. Theflame filter will typically have a thickness in the range of about0.25-0.75 inches, but the thickness of the filter can also be as greatas 1 or 2 inches or greater in the invention. The thickness of thefilter will depend somewhat on the amount of mixing provided by thefilter structure (e.g. pore sizes), and the thermal conductivity of thefilter material. High mixing capability (e.g. small pore size, and areticulated structure) and high thermal conductivity will allow for athinner filter. Thicker filters are required if the pore size is large(e.g. 0.1 inch), and the filter has a low thermal conductivity (e.g.below 10 W/mK)

The flame filter 36 may be cylindrically shaped (although it is notnecessarily cylindrical), with a diameter 56. The diameter may beselected to be within the range of about 0.125-1.0 inches (i.e. crosssectional area of about 0.015 square inch to about 1 square inch). Thepresent invention includes embodiments where the flame filter is largeror smaller than this range. In one embodiment, the cross sectional areais about 0.1 to about 0.5 square inches. The present invention alsoincludes embodiments where the flame filter is square, rectangular orany other shape in cross-section.

The porous flame filter 36 is essential in the invention. The flamefilter 36 can be made of many different materials and structures, all ofwhich are understood to be included in the invention and within thescope of the appended claims. Materials and structures suitable for theflame filter include:

Bonded granules—In this embodiment, the flame filter is made of granulesof heat resistant materials bonded or sintered together. Examplesinclude sintered bronze, brass, stainless steel, or other metals. Alsoincluded are sintered ceramics such as alumina, cordierite, orporcelain. Bonded silicon carbide granules can be used as well. Thegranules can have sizes in the range of about 100-2000 microns, forexample. If metals are used, a chemically stable coating (e.g. gold orplatinum) can be applied to prevent oxidation. The porosity (volume % ofopen space) should be relatively high, for example at least 20 or 30%.The pore size should be relatively large so that one can inhale easily;for example, the pore size can be about 100-1000 microns.

Stack of plates or screens—The flame filter can comprise a stack of atleast two, preferably at least three or four metal screens. For example,conventional metal screens can be. used. In this case, the metal shouldhave a relatively high thermal conductivity above about 30 W/mK (e.g.brass or silver). Also, the metal may be resistant to oxidation, or havea protective coating (e.g. gold or platinum). Alternatively, the flamefilter can comprise a stack of at least two, preferably at least threeor four ceramic or metal plates with holes. A series of plates withholes is considered to be ‘porous’ in the present invention and appendedclaims.

Metal wire—The flame filter can also comprise a web of metal wire (e.g.20-30 gauge). The metal may be resistant to oxidation or have aprotective coating (e.g. platinum or gold), and have a high thermalconductivity (e.g. copper, brass or silver). The metal wire can betangled, coiled, folded or in any other configuration that createsmixing of air and flame exhaust and provides heat exchange. The metalwire can have a round cross-sectional shape, or can be flat ribbon.

Reticulated open-cell foam—The flame filter can also comprise open cellmetal or ceramic foam. In this case, the foam can have a pores-per-inch(PPI) rating of about 30-120, more preferably in the range of 50-100PPI, inclusive. If metal is used, it should be heat resistant, andpossibly coated with a protective coating (e.g. gold, platinum or otherplatinum-family metals). If ceramic is used, the foam can be made byapplying a ceramic slurry to a burnable (e.g. urethane) foam substrate,and then kiln-firing, as known in the art. Also, the ceramic foam can bemade by chemical vapor deposition (CVD) onto a foam substrate, also asknown in the art. If CVD ceramic foam is used, it can be made of siliconcarbide, which has very high oxidation resistance and thermal shockcapability, is relatively inert, and has high thermal conductivity,which are all desirable properties. CVD ceramic foam can also be made ofsilicon, which also has high thermal conductivity and heat resistance.Other possible materials for the ceramic foam include cordierite,zirconium-containing ceramics, or silica-containing ceramics, orcombinations of these materials. Some ceramic materials may break apartor crack due to the thermal shock of the applied flame, which isundesirable. Hence, a ceramic material should be selected that canwithstand the thermal shock. A particularly useful material for theflame filter is 80 PPI CVD silicon carbide open-cell foam. The foam mayhave a relative density (volume occupied by solid material) of about5-25% or about 8-12%. It is also noted that not all of the cells need tobe open; some cells can be closed, as often occurs in ceramic foam madefrom slurry applied to polymer foam.

Most generally, the flame filter can comprise any heat-resistant, porousmaterial that causes mixing of and/or heat exchange between of the flameexhaust and air, and has a thickness of at least 0.02 inches, or atleast 1 millimeter or 0.1 inches. Reticulated structures such as opencell foams are preferred, but the invention and appended claims includeall the materials listed above. The flame filter should resist meltingup to at least the temperature of the flame of course, and preferablyresists oxidation up to about 1000 degrees Fahrenheit. Some oxidation isacceptable if it forms a protective coating. Also, the material of theflame filter (i.e. not including pore spaces), may have a thermalconductivity of at least 30 W/mK. Silicon carbide can have thermalconductivity of about 120 W/mK, and so provides good heat transfer. Ahigh thermal conductivity facilitates heat transfer between the flameexhaust and ambient air, thereby ensuring that the intermediatetemperature air stream has a uniform temperature.

The flame filter can have a protective coating (e.g. platinum) toprotect it from oxidation and chemical reactions. A protective coatingcan be particularly useful in embodiments employing metals, such asmetal wire or sintered metal granules.

It is also noted that the flame filter 36 can have a combustioncatalytic coating (e.g. platinum or palladium or a combination thereof)for causing more complete combustion of the flame exhaust. This willtend to reduce the amount of harmful combustion products inhaled fromthe flame.

Also, it is noted that the filter can include means (e.g. threads,friction fit) for direct attachment to the pipe. Preferably, the flamefilter is disposed in a filter housing, because the flame filtertypically gets too hot to safely handle directly. If a filter housing isused, the flame filter can be attached to the pipe indirectly throughthe filter housing. It is understood that the flame filter is consideredattached to the pipe even in embodiments where the flame filter isdirectly attached only to the filter housing.

It is noted that the filter unit 34 can attach to the pipe with manydifferent mechanisms. Examples include magnetized components that attachby magnetic attraction, screw threads as shown in FIGS. 1 and 2,friction fit (with or without O-rings) hinges, springed clamps and thelike.

It is noted that it is preferable for the bowl to be constructed suchthat air flows in a straight path through the smoking material (as inall the pipes shown). In other words, the air preferably exits thebottom of the bowl, opposite the filter. This tends to result in all thesmoking material being exposed to the hot airflow. In some conventionalpipes (e.g. large conventional tobacco pipes), by contrast, the bowl isconstructed so that air exits the side of the bowl, thus requiring thatthe hot air make a 90-degree turn within the bowl. This tends to resultin unvaporized smoking material on the side of the bowl furthest fromthe bowl exit, which is undesirable.

FIGS. 4 a and 4 b illustrate an alternative embodiment of the inventionwhere the filter unit 34 is attached to a straight pipe 55 with a hinge56. The hinge allows the smoking material 28 to be inserted, and removedwhen it is spent. It is understood that a hinge attachment is consideredto be an example of a ‘removable’ attachment in the present inventionand appended claims.

FIG. 5 shows an alternative embodiment where the filter unit 34 isattached to the straight pipe by sliding over the straight pipe 55 witha friction fit. An O-ring (not shown) can be disposed between the filterhousing 38 and the straight pipe 55.

FIG. 6 shows an embodiment of the invention having a stack of 6 screens58 as the flame filter. The screens can be made of metal mesh, forexample, or ceramic. The filter unit 34 fits onto a pipe 57 with afriction fit, for example. The screens 58 may be spaced apart as shown,or may be in contact. A series of screens is considered to be ‘porous’in the invention.

FIG. 7 shows an embodiment where the flame filter comprises a web ofmetal wire 60. The wire can be 20-30 gauge, for example, and can beround or flat. The wire can be tangled, as shown, or can be coiled orfolded in an organized fashion.

FIG. 8 shows a close-up of the filter unit 34 in an embodiment where theporous flame filter comprises a series of 5 discs 61 a-61 e, with eachdisc having holes 64. The discs can be made of metal or ceramic or anyother heat-resistant material, for example. The discs have holes indifferent locations, so that ambient air and flame exhaust follow atortured path 62. The tortured path creates mixing between the flameexhaust and the ambient air, as required in the present invention. Thedisc material may or may not be porous, but the combination of stackeddiscs is considered porous in the invention. The number is discs can bein the range of about 3-20, for example. Each disc can have one or moreholes.

FIG. 9 a shows a group of 5 discs that can be used in the embodiment ofFIG. 8. Each disc has the same hole pattern, but each disc is rotated sothat the holes in adjacent discs are not overlapping. This assures thatthe flame exhaust and ambient air follow a tortured path and are mixedas they pass between the discs. FIG. 10 shows an alternative group ofdiscs 61 having elongated holes 64 arranged in a striped pattern. Thediscs can be round (as shown), or square, rectangular or any othershape. The discs can have a wide range of thicknesses.

FIG. 11 shows yet another embodiment of the filter unit 34 wherein theflame filter 36 is combined with a disc 70 over the flame filter 36. Thedisc 70 has holes 72 around the periphery. The holes 72 are located atthe periphery, and so tend to direct heat toward the periphery of thefilter, and thereby create a more uniform heat distribution in thesmoking material. Without the disc 70, sometimes the temperature can betoo hot in the center, and too low at the edges. FIG. 12 shows a topview of the disc. The disc can have any number of holes (e.g. 3-10), andthe holes can be any shape. The disc 70 can also be located under (onthe downstream side of) the flame filter 36. The embodiment of FIGS. 11and 12 is most useful where the flame filter 36 comprises a reticulatedstructure such as foam or bonded granules. In an alternative embodiment,the disc 70 has no holes, and has a smaller diameter than the flamefilter 36, so that it directs airflow to the periphery. The disc 70 canbe bonded to the flame filter 36.

FIG. 13 shows another embodiment having an electronic temperatureindicator 80 coupled to a temperature sensor 82 such as a thermistor orthermocouple. The temperature sensor 82 should be located close to thesmoking material 28. The temperature sensor can be located behind(downstream from) the smoking material, as shown, or can be locatedbetween the flame filter 36 and the smoking material 28. In operation,the display 80 provide the user with an indication of the temperature atthe smoking material. This is useful for some users who have difficultlyadjusting the flame application to achieve the best vaporizationtemperature. The display may have an LED, or liquid crystal element toindicate an approximate temperature to the user, for example with a bardisplay. By using the display, the user can more accurately adjust thetemperature inside the smoking material 28.

FIG. 14 shows another aspect of the invention wherein the pipe includesa thermo-mechanical airflow shutter 84 for controlling airflow inresponse to temperature. In the present vaporization pipe, the amount ofairflow influences the temperature at the smoking material.Specifically, for a constant flame size, higher airflow (strongerinhalation) results in cooler temperature, since higher airflow requiresmore ambient air. Hence, the thermomechanical shutter 84 can maintain asomewhat constant temperature by restricting airflow when temperature istoo low. More specifically, the shutter 84 opens when is it exposed toexcessive temperature (e.g. temperatures that can cause burning),thereby allowing more ambient air, and reducing the temperature. Theshutter can be made of a bimetallic strip partially blocking the airpassage. When exposed to high temperature, the shutter 84 bends to openthe airway. Many different shapes and structures can be used for theshutter 84. FIGS. 15 a and 15 b, for example, show top views of ashutter made of bimetallic sheet at low and high temperature,respectively. Leaves 86 of the shutter curl in a direction out of thepage when exposed to excessive temperature, and thereby allow moreairflow when exposed to excessive temperature. The shutter 84 can belocated between the flame filter 36 as shown, or can be placed below thesmoking material 28 (i.e., within the pipe bottom). In an alternativeembodiment, the shutter allows air directly from ambient (not throughthe flame filter), when the temperature is excessive.

FIG. 16 shows yet another embodiment of the invention having atemperature indicator. Specifically, the device has a thermomechanicalelement (e.g. bimetallic strip) 86 that responds to temperature byraising or lowering a rod 88 through a hole 90. The height of the rod 88indicates the approximate temperature experienced by the smokingmaterial 28.

FIG. 17 shows yet another embodiment of the invention where the filterhousing 38 is permanently bonded to the bowl. The bowl 26 is providedwith a door 100 through which smoking material 28 is loaded into thebowl. The door 100 can open and close. When closed, the door should beair tight, or nearly airtight. In one embodiment, the screen 30 can bewithdrawn from the bowl 26 through the door 100 and filled with smokingmaterial 28. Then, the smoking material 28 and screen 30 are loaded intothe bowl through the door 100. In the embodiment of FIG. 17, the filteris not removably attachable to the pipe.

FIG. 18 shows another embodiment of the invention where a portion of thefilter housing 38 and bowl 26 form the door 100 that can be opened toprovide access to the smoking material 28. The door 100 pivots on ahinge 102 and is shown in its open position. The flame filter 36 can beattached to the hinged portion of the filter housing, or the stationaryportion of the filter housing. In the specific embodiment of FIG. 18,the flame filter 36 is attached to the stationary, unhinged portion ofthe filter housing.

FIG. 19 shows another embodiment in which the filter housing 38 and pipe20 attach by means of a conical ground glass joint 100. The pipe 20comprises a female joint 102, and the filter housing 38 comprises a malejoint 104. The smoking material is disposed in the bottom of the femalejoint 102, and the flame filter 36 is disposed in the male joint 104.The ground glass joint 100 is illustrated as conical, but can also bespherical or any other shape. The ground glass joint may be airtight.The pipe 20 and filter housing 34 can be entirely made of glass forexample. FIG. 20 shows an alternative embodiment in which the male jointis hollow.

FIG. 21 shows another design of the vaporizing pipe. The filter housing38 comprises a male joint. The bowl 26 is disposed downstream from thefemale joint 104. The male joint. filter housing 38 includes an optionalstep 106. The step 106 provides a support for holding the flame filter.36. The step can be about 1 mm thick for example, and provide about 1-4mm of diameter constriction for supporting the flame filter. Also aretaining ring 107 (e.g. comprising a wire loop) can be disposed abovethe flame filter. The retaining ring 107 assures that the flame filterdoes not fall out of the filter housing 38. FIG. 22 shows the pipe ofFIG. 21 in use. A lighter flame is drawn into the flame filter 36, whichmixes flame exhaust with ambient air to create vaporizationtemperatures.

FIG. 23 shows another embodiment in which the bowl 26 is disposed in amale joint 108, and the filter housing 38 comprises a female joint 110.The filter housing 38 also includes an optional glass tube 112 attachedto the female joint 110. The filter housing 38 can include a step 106for supporting the filter. The pipe 20, male joint 108, bowl 26, femalejoint 110 and tube 112 can be made of glass such as borosilicate glass.

FIG. 24 shows a magnified view of the filter housing 38 and male joint108 and bowl 26 of FIG. 23, without the pipe 20. The filter housing 38may include the step 106 for supporting the flame filter 36. Also aretaining ring 107 can be provided for securing the flame filter 36 toassure it does not fall out.

Optionally, an air gap exists between the flame filter 36 and the glass(e.g. glass tube 112 or male joint 102). The air gap can be0.002″-0.040″ thick, for example. An air gap will tend to minimize theamount of heat dissipated into the glass.

FIG. 25 shows another embodiment made in glass. An O-ring 114 isdisposed between the filter housing 38 and the bowl 26. The O-ringprovides friction so that the filter housing and bowl 26 can be securelyattached. Both the bowl 20 and the filter housing can be made of glass.

FIG. 26 shows another embodiment having a glass finger 120. The glassfinger is connected to the top of the male joint, and extends downwardto the filter 36. The finger holds the filter in place so that it cannotfall out. The finger can be fused to the filter, or can be unconnectedto the filter. The finger can be in contact with the filter, or slightlyabove it. The filter may have a small amount of space (e.g. 1-3 mm) tomove vertically between the step 106 and the finger 120.

The present invention is also directed toward only the filter unit,which has a flame filter inside the filter housing, and a means forattaching the filter housing to a pipe. The means for attaching the pipecan be a threaded connection, magnet, clamp, hinge, ground glass joint,O-ring seal, and the like. The present filter unit can be used with manydifferent kinds of pipes and devices ordinarily intended for use asconventional smoking devices. In fact, the present filter unit caneffectively transform a conventional smoking pipe into a vaporizationdevice. For example, the filter unit can be combined with a water pipeor any other pipe known in the art, and the pipe will act as avaporizer.

It is also noted that the present invention can be used to producesmoke, if desired. If smoke is desired, a large flame is provided to theflame filter. Smoke produced in the present device will tend to besmoother and more pleasant than smoke produced in a conventional pipe,but will contain the harmful substances known to occur in smoke.

It is noted in the present invention that ceramic materials aregenerally preferred over metals for use in the flame filter 36. This isbecause ceramics tend to be much more resistant to oxidation andcorrosion at high temperatures. Metals such as brass, copper or bronzetend to oxidize, which produces unhealthful metal oxide particles, whichare inhaled. Also, metal flame filters tend to create a metallic taste.Inert metals such as platinum or gold can be used (e.g. as a coating),but such materials are very expensive. Hence, relatively inert ceramicssuch as silicon carbide, silicon, cordierite, and zirconia arepreferred. It is also noted that semiconductor materials such as siliconcan be used for the flame filter (e.g. silicon foam), and such materialsare understood to fall under the rubric of ceramic materials in thepresent disclosure. Nevertheless, it is understood that even oxidizablemetals (e.g. brass, bronze, steel) will function to provide flamefiltering and air mixing, and are therefore included in the presentinvention and scope of the appended claims.

Also, it is noted that combinations of materials can be used for theflame filter. For example, the flame filter can comprise a screen incombination with a metal or ceramic foam, or a coil of wire incombination with ceramic discs having holes.

It will be clear to one skilled in the art that the above embodimentsmay be altered in many ways without departing from the scope of theinvention. Accordingly, the scope of the invention should be determinedby the following claims and their legal equivalents.

1. A method for vaporizing smoking material, comprising the steps of: a)disposing smoking material in a bowl of a pipe having an inhalation end;b) disposing a heat resistant and porous flame filter upstream from thebowl; c) inhaling from the inhalation end so that flame exhaust is drawninto the flame filter, and the flame exhaust is mixed with ambient airin the flame filter; d) drawing the flame exhaust and ambient airmixture through the smoking material such that volatile components ofthe smoking material are vaporized.
 2. A vaporization device,comprising: a) a pipe having: 1) a bowl for holding smoking material,and 2) an inhalation end for emitting vapors, wherein the inhalation endis disposed downstream from the bowl; b) a heat resistant and porousflame filter, with tortured flow paths, for receiving a flame, whereinthe flame filter has a thickness of at least 0.02 inches, and whereinthe flame filter is disposed upstream from the bowl; c) a filter housingfor holding the flame filter, wherein the filter housing and the pipeattach via a ground glass joint or O-ring seal.
 3. The vaporizationdevice of claim 2, wherein the flame filter comprises a materialselected from the group consisting of open cell foam, open cell ceramicfoam, bonded granules, stacked discs, tangled wire, stacked screens, andcombinations thereof.
 4. The vaporization device of claim 2, wherein thefilter housing comprises a male joint, and the pipe comprises a femalejoint.
 5. The vaporization device of claim 2, wherein the filter housingcomprises a female joint, and the pipe comprises a male joint.
 6. Thevaporization device of claim 2, wherein the ground glass joint isconical or spherical.
 7. The vaporization device of claim 2, wherein thefilter housing includes a step for supporting the flame filter.
 8. Thevaporization device of claim 2, further comprising a retaining ringdisposed in the filter housing, for retaining the flame filter.
 9. Thevaporization device of claim 2, further comprising a finger attached tothe filter housing, for retaining the flame filter.
 10. The vaporizationdevice claim 2, wherein the flame filter comprises silicon carbideceramic foam and has a thickness of at lest 0.05 inches.
 11. A filterunit for attachment to a pipe having a bowl for holding smokingmaterial, and having an inhalation end for emitting vapors, wherein theinhalation end is disposed downstream from the bowl, the filter unitcomprising: a) a filter housing; b) a heat resistant and porous flamefilter disposed in the filter housing, wherein the flame filter has athickness of at least 0.02 inches, and wherein the flame filtercomprises a material selected from the group consisting of open cellfoam, open cell ceramic foam, bonded granules, stacked discs, tangledwire, stacked screens, and combinations thereof; wherein the filterhousing comprises a male or female ground glass joint for attaching thefilter housing to the pipe such that the flame filter is disposedupstream from the bowl.
 12. The filter unit of claim 11, wherein thefilter housing comprises a male joint, and the pipe comprises a femalejoint.
 13. The filter unit of claim 11, wherein the filter housingcomprises a female joint, and the pipe comprises a male joint.
 14. Thefilter unit of claim 11, wherein the filter housing includes a step forsupporting the flame filter.
 15. The filter unit of claim 11, whereinthe flame filter comprises silicon carbide ceramic foam.
 16. The filterunit of claim 11, wherein the flame filter has a thickness of at least0.05 inches.